Project Summary Dr. Jacqueline S. Garcia is an Instructor in Medicine at Harvard Medical School/Dana Farber Cancer Institute (DFCI) with research interests in the biology of relapsed acute myeloid leukemia (AML) and therapeutics targeting chemoresistance. The applicant, Dr. Jacqueline Garcia, presents a 5-year career development program designed to support an academic, clinical/translational investigator. The proposed research project will take advantage of the clinical and scientific expertise and resources available at the DFCI, which has a long-tradition of training clinical investigators. This includes a mentorship committee led by Dr. Richard Stone, a highly qualified and internationally recognized AML clinical trialist. This research will promote training in areas critical to Dr. Garcia?s career goals: clinical research methods, principles of human research, and translational research tools as it pertains to conducting patient-oriented investigations. Her long-term goal is to be an independent leukemia investigator and develop novel scientifically-sound clinical trials for patients with relapsed AML. This proposal seeks to gain biological understanding of the role of functional assays in leveraging the activity of venetoclax- based therapies in chemoresistant AML settings to prevent and treat relapse. Key mediators of the anti-apoptotic pathway determine the cellular response to chemotherapy. Biological tools such as the BH3 profiling assay, developed by her co-mentor Dr. Anthony Letai, offers the unique opportunity to evaluate a myeloblast?s readiness to undergo apoptosis (based on cytochrome c release in the presence of BH3 peptides) and its anti-apoptotic dependencies. Dr. Letai has also developed a drug-specific BH3 profiling assay called dynamic BH3 profiling (DBP) which measures apoptotic priming following short-term ex vivo drug exposure. Preliminary data shows that DBP predicts in vivo response to individual or a combination drugs after short-term ex vivo drug exposure. Venetoclax, a selective BCL-2 inhibitor and BH3 mimetic, is an active drug in acute myeloid leukemia but requires a drug partner(s) to boost its potency. Her central hypothesis is that BH3 profiling tools will identify effective personalized drug combinations that will enhance the activity of venetoclax in patients with chemoresistant myeloblasts. The work outlined in this proposal will use BH3 profiling assays to examine the role of venetoclax immediately prior to transplant to reduce relapse and at time of relapse. She proposes to: (Aim 1) determine the impact of adding venetoclax to conditioning chemotherapy on the risk of relapse after transplantation for patients with poor risk MDS and AML, (Aim 2) characterize the mitochondrial apoptotic priming state in myeloblasts at diagnosis and upon progression on combination venetoclax and hypomethylating agents to understand acquired resistance, and (Aim 3) determine the impact of using DBP to guide optimal venetoclax-based drug combinations to improve response in relapsed AML. If successful, this project will provide evidence of direct clinical translation from the laboratory and provide a new approach for identifying personalized AML therapies.